A digital oscilloscope is a type of electronic test instrument used to observe electrical signals. A user of a digital oscilloscope typically applies an oscilloscope probe to a device under test (DUT) to measure a signal of interest. The oscilloscope probe then transmits the signal to an analog to digital converter (ADC), which converts the signal into a stream of digital samples. The stream of digital samples is then transmitted to a data acquisition system where it is processed and stored for subsequent display as a digital waveform.
The data acquisition system generally operates in periodic update cycles. For example, in a typical update cycle, it captures a predetermined number of digital samples from the stream, processes the captured samples (e.g., with trigger or timebase controls), and transmits them to a display system to be presented as a waveform. Between consecutive update cycles, there may be dead-time in which the data acquisition system does not store and capture portions of the stream of digital samples. In other words, the data acquisition system may ignore some of the available information. This can present problems, for instance, if the user is unable to observe glitches occurring at regular intervals that happen to fall within the dead-time.
In addition to ignoring some of the available information, conventional digital oscilloscopes may also be limited in the way they measure and display the sampled data. For example, most conventional oscilloscopes do not generate continuous measurements commonly found on digital voltmeters (DVMs), such as numerical displays of root mean squared (RMS) voltages or minimum and maximum voltages. Accordingly, a user desiring these types of measurements may be required to use both an oscilloscope and a DVM to measure the characteristics of a single DUT.
In view of these and other shortcomings of conventional digital oscilloscopes, there is a general need for digital oscilloscopes that can provide improved measurement and display capabilities without excessive cost or complexity.